Strap-tightening tool.



W. D. MACDONALD.

STRAP TIGHTENING TOOL. APPLICATION FILED JULY 6. 191a.

PatentedSept. 3,1918.

anvenfoz STATES PA TENT OFFICE.

WILLIAM DUNCAN MACDONALD, OF YONKEBS, NEW YORK, ASSIGNOB TO E. J. BROOKS & COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

STBAIP-TIGHTENING TOOL.

Specification of Letters Patent.

Patented Sept. 3, 1918.

Application filed July 6, 1918. Serial No. 248,664.

To all whom it may concern:

Be it known that I, WILLIAM DUNCAN MACDONALD, a citizen of the United States, and a resident of Yonkers, in the county of Westchester and State of New York, have invented certain new and useful Improve- .nents in Strap-Tightening Tools, of which the following is a specification.

The resent invention relates to tigthening too s and more particularly to that type used for tightening straps or bands of sheet metal that are placed around packages or bales and which are subsequently sealed in a known manner by means of a metallic seal; and has for its object means whereby straps or bands of material may be tightened in a simple and eflicient manner. With this object in view, the invention consists of a pawl and a detent, the sawl being mounted in a rockin lever'an engaging with the'material to. e tightened when the lever is moved in one direction, the detent.

also engaging with the material and acting to prevent retrograde movement thereof when the lever is moved in the opposite direction.

In the accompanying drawings the invention is embodied in a concrete and preferred form, in which:

Figure 1 is a side elevation of a strap ti htening tool partly in section.

dig. 2 1s ,a perspective view of the pawl; an

Fig. 3 is a perspective view of the detent.

1 indicates a support of any suitable construction, here consisting of a plate having a roughened surface 2 upon which the free ends 3 and 4 of a strap are placed. In this instance, the strap shown is in the form of a ribbon of sheet material such as isused in connection with boxes or bales containing goods. It will be understood that this strap is passed around the package and, before the metallic seal .is" a plied to the free ends of said strap, the atter must be tightened around the package especially when a bale with flexible covering is to be protected.

5 is a lever pivotally supported at 6 in the side wall 7 that forms a guide above the surface 2. On this lever a pawl 8 is mounted by being pivotally connected thereto at 9 and held in spring-pressed engagement with said lever by means of a spring 10 actin against an extension 11 o the pawl.

spring 12 normally urges lever 5 into the position shown in Fig. 1, said spring having a bearing on the stationary handle or abut depressed into the position indicated indotted lines, pawl 8 moves unyieldingly with the lever and its outer end engages the strap, biting into the material thereof, and advances the upper free end 3 to the left, in Fig. 1, while the lower free end 4 is retained in the position it occupies. During the feeding stroke of lever 5, detent 14 will turn slightly on its pivot 15 so as to admit of the passage of the free end 3 to the left under the action of pawl 8. When pawl *8 has reached the extreme end of its feeding stroke, lever 5 may be released and spring 12 will then tend to restore the lever to its original position. While this is occurring, spring 10 will yield sufiiciently to admit of pawl 8 slipping back without undue pressure being exerted on the free end 3 of the In addition to this, detent 14 will,

strap. durmg the return stroke of lever 5,'press firmly against said free end 3, thereby preventing any possibility of a retrograde movement of the material. After the strap has been tightened 'suificiently, the metallic seal is secured around the free ends thereof b ported at 18'in the side wall 7 and provided with one projection 19 that engages extension 11 of pawl 8, a portion of the member 17 itself engaging with extension 20 of detent 14. It Wlll be understood that by depressing member 17 both pawl 8 and detent 14 are swun around their pivotal centers, 9 and 15, an thus release the strap.

It will be evident that if it is desired to' use the tool for material of different thicknesses, the support 2 may, in a known manner, be made adjustable with reference to the pawl and detent.

- 1 claim:

A strap tightening tool comprising: a sup port for material to be tightened, a rocking lever, a pawl for engaging with the material to be tightened pivotally supported on said lever, va spring for normally urging one end or said pawl into engagement with the lever to 'a'fiord an unyielding movement of said pawl with the lever during the feeding stroke of the latter and to permit aylelding movement independently of the lever during the return stroke thereof, means for normally urging the lever into the position it occupies at the end of its return stroke, a detent also engaging with the material and pivotally mounted, a spring normally urging said detent into engagement With the material to be tightened to oppose retrograde movement of said material during the return strokev of the lever and to yield to admit of the pgassage of material during the feeding stro e of the lever, and means for counteracting the eflect of the springs hearing against-the pawl and detent to elevate same out of engagement With the material.

Signed at Yonkers, inthe county of Westchester and State of New York, this 2 day of July, 1918. I

WILLIAM DUNCAN MACDONALD. 

